Thermal Reaction and Phase Evolution of APP/Al(OH)3/α-SiO2

2016 ◽  
Vol 680 ◽  
pp. 547-552
Author(s):  
Sheng Hu ◽  
Wan Wan Sun ◽  
Fei Chen ◽  
Jun Guo Li ◽  
Qiang Shen ◽  
...  

The thermal reaction and phase evolution of APP/Al (OH)3/α-SiO2 with different mass ratios during heating were studied by TG, FTIR, XRD and SEM, respectively. When the temperature is not higher than 300 oC, mass ratio of mAPP:mAl (OH)3:mSiO2 has no effect on the phase evolution of APP/Al (OH)3/α-SiO2 and the main interaction product is AlNH4HP3O10. APP/Al (OH)3/α-SiO2 with lower content of APP, appears larger weight loss rate due to the thermal decomposition of Al (OH)3. The thermal reaction of APP/Al (OH)3/α-SiO2 is significantly influenced by the APP content as temperature rises to higher than 300 oC. The decomposition products of APP can chemically interact with Al (OH)3 to generate Al2P6O18 and Al (PO3)3 during 600 oC ~900 °C. When the content of APP increases, much more APP can chemically react with Al (OH)3 and also with part of α-SiO2 to generate SiP2O7. SEM shows the relatively dense microstructure due to micro-bridges of liquid phase with phosphate content increasing.

2018 ◽  
Vol 225 ◽  
pp. 02002 ◽  
Author(s):  
Girma T. Chala ◽  
Ying P. Lim ◽  
Shaharin A. Sulaiman ◽  
Chin L. Liew

This paper presents the characteristics of empty fruit bunch (EFB) using thermogravimetric analysis (TGA) and shows its potential as a renewable energy sources. A set of data were collected from the thermal reaction and plotted in mass or percentage of the initial mass against either temperature or time, respectively. In the thermogravimetric analysis, mass, temperature and time were considered as base measurements and important data for derivative thermogravimetric (DTG) curve were analysed while many additional measures could be derived from these three base measurements. It was observed that heating rate of 8.5°C/min and air flow rate of 85mL/min provided a maximum weight loss rate of 0.209%/°C at the temperature of 313.5°C and the derivative weight peak of -0.1895mg/°C at 292°C. The time taken to reach the maximum temperature of 899.9°C was 46.74 minutes, and ΔT endo-up reflected minimum point of -0.2°C at 15.82 minutes and maximum ΔT endo-up of 888°C at 42 minutes. Heat flow endo-up also showed that the minimum heat flow was 15.39mW at 15.85 minutes and reaching the peak heat flow endo-up of 47.73mW at 43.27 minutes.


2021 ◽  
pp. 095400832199674
Author(s):  
Tao Guo ◽  
Yang Fan ◽  
Chang Bo ◽  
Zhang Qi ◽  
Han Tao ◽  
...  

Benzoxazine resin exhibits excellent properties and is widely used in many fields. Herein, the synthesis of a novel compound, the bis(2,4-dihydro-2 H-3-(4- N-maleimido)phenyl-1,3-benzoxazinyl)biphenyl (BMIPBB), has been reported, which was synthesized by reacting N-(4-aminophenyl)maleimide (APMI), formaldehyde, and 4,4’-dihydroxybiphenyl. 1,3,5-three(4-(maleimido)phenyl)-1,3,5-triazine (TMIPT) was formed as an intermediate during the reaction. The proton nuclear magnetic resonance (1H-NMR) and Fourier transform-infrared (FTIR) spectroscopy experiments were conducted to determine the structure of BMIPBB. BMIPBB was obtained as a reddish-brown solid in 40.1% yield. The thermal properties of BMIPBB were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Analysis of the DSC curves revealed that the broad peak representing the release of curing reaction heat appeared in the temperature range of 140–330°C. The peak temperature was 242.59°C and the heat of the reaction was 393.82 J/g, indicating that the rate of the curing reaction was low and the heat of the reaction was high. Analysis of the TGA results revealed that the weight loss rate was 5% at 110°C. The monomer exhibited a significant weight loss in the range of 320–500°C. The compound lost 50% of its weight at a temperature of 427°C.


2018 ◽  
Vol 33 (4) ◽  
pp. 605-609
Author(s):  
Hiroki YABE ◽  
Mizuki TSUKAMOTO ◽  
Shihomi TAKEUCHI ◽  
Sayaka ITO ◽  
Kan OMI ◽  
...  

2011 ◽  
Vol 418-420 ◽  
pp. 55-58 ◽  
Author(s):  
Yun Long Ai ◽  
Fei He ◽  
Bing Liang Liang ◽  
Wen He ◽  
Li Liu

The influences of Nb2O5on the phase, microstructure and hydrochloric acid corrosion behaviors of Nb2O5-Al2O3ceramics sintered with 2.45 GHz microwave energy were investigated. The results showed that Nb2O5 reacted completely with Al2O3to form AlNbO4and densified the pure Al2O3at a lower sintering temperature and in a short sintering time. Nb2O5-Al2O3ceramic samples were corroded in diverse concentration hydrochloric acid for different time. Weight loss rate of Nb2O5-Al2O3ceramic rose dramatically when the corrosion time was not longer than 4 h, and it increased slowly beyond 24 h. After Nb2O5-Al2O3ceramic samples were corroded for 1 h, pitting corrosion was observed by scanning electric microscope, which was consistent with the analysis results of the scanning Kelvin Probe.


2020 ◽  
Vol 636 ◽  
pp. L3 ◽  
Author(s):  
M. Fulle ◽  
J. Blum ◽  
A. Rotundi

Context. An open question in the study of comets is the so-called cohesion bottleneck, that is, how dust particles detach from the nucleus. Aims. We test whether the CO pressure buildup inside the pebbles of which cometary nuclei consist can overcome this cohesion bottleneck. Methods. A recently developed pebble-diffusion model was applied here to comet C/2017K2 PANSTARRS, assuming a CO-driven activity. Results. (i) The CO-gas pressure inside the pebbles erodes the nucleus into the observed dust, which is composed of refractories, H2O ice and CO2 ice. (ii) The CO-driven activity onset occurs up to heliocentric distances of 85 au, depending on the spin orientation of the comet nucleus. (iii) The activity onset observed at ≈26 au suggests a low obliquity of the nucleus spin axis with activity in a polar summer. (iv) At 14 au, the smallest size of the ejected dust is ≈0.1 mm, consistent with observations. (v) The observed dust-loss rate of ≈200 kg s−1 implies a fallout ≥30%, a nucleus surface active area ≥10 km2, a CO-gas loss rate ≥10 kg s−1, and a dust-to-gas ratio ≤20. (vi) The CO-driven activity never stops if the average refractory-to-all-ices mass ratio in the nucleus is ≤4.5 for a nucleus all-ices-to-CO mass ratio ≈4, as observed in comets Hale–Bopp and Hyakutake. These results make comet C/2017K2 similar to the Rosetta target comet 67P/Churyumov–Gerasimenko. (vii) The erosion lifetime of cometary planetesimals is a factor 103 shorter than the timescale of catastrophic collisions. This means that the comets we observe today cannot be products of catastrophic collisions.


Author(s):  
Junping TAN ◽  
Xian ZHOU ◽  
Shuiyuan CHENG ◽  
Zexiong CHEN ◽  
Yuanyuan GOU ◽  
...  

Kombucha is sweetened, slightly alcoholic, and lightly effervescent tea drink. Its acidity inhibits the growth of harmful bacteria. Here, we studied effect of kombucha on post-harvest preservation of pear. The Hosui pears were soaked with the kombucha for 15 minutes, and in distilled water as the control, respectively. Superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), hydrogen peroxide (H2O2), proline content, electric conductivity, weight loss rate and good fruit rate in pear were measured during storage at room temperature. The results showed that the kombucha could effectively prolong the storage time of pear fruit. The fruit quality of the treated group was 1.5 times higher than that of the control pear fruit when stored at room temperature for 18 days. The weight loss rate, MDA content and electric conductivity of the treatment group were lower than those of the control group during the whole storage period, indicating that kombucha can inhibit the transformation of polysaccharides such as starch and pectin, and delay the degradation of nutrients in the fruit, resulting in a decrease in weight loss rate, inhibition of membrane lipid peroxidation, reducing MDA content, electric conductivity, maintaining cell membrane stability, delaying pear fruit senescence. Kombucha can inhibit the content of H2O2 and proline, increase the activity of POD and SOD increase the storage stability of fruits. The purpose of this study was to elucidate the physiological mechanism of post-harvest preservation of pear by kombucha. The use of kombucha can prolong the supply period of pear, increase economic benefits and expand the market of pear.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********


2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Zhulin Liu ◽  
Xuegong Bi ◽  
Zeping Gao ◽  
Wei Liu

Carbon-containing pellets were prepared with the carbonized product of agricultural wastes and iron concentrate, and an experimental study on the direct reduction was carried out. The experimental results demonstrated that carbon-containing pellets could be rapidly reduced at 1200 to 1300°C in 15 minutes, and the proper holding time at high temperature was 15 to 20 min. The degree of reduction gradually increased with temperature rising, and the appropriate temperature of reducing pellets was 1200°C. The weight loss rate and reduction degree of pellets increased with the rise of carbon proportion, and the relatively reasonable mole ratio of carbon to oxygen was 0.9. A higher content of carbon and an appropriate content of volatile matters in biomass char were beneficial to the reduction of pellets. The carbon-containing pellets could be reduced at high speeds in the air, but there was some reoxidization phenomenon.


Author(s):  
Isao Yuri ◽  
Tohru Hisamatsu ◽  
Shunkichi Ueno ◽  
Tatsuki Ohji

In order to understand recession behavior and the amount of recession of Lu2Si2O7 in the combustion gas flow, sintered Lu2Si2O7 specimens were manufactured by hot pressing and exposed under various combustion gas flow conditions (T = 1300–1500 °C, P = 0.3 MPa, V = 150 m/s, PH2O = 27–69 kPa, t = 10h). After the exposure tests, etch pits, which are assumed to form due to volatilization of SiO2 in the grain boundary phase, were observed at the surface of specimen. The amount of Lu2SiO5 phase at the surface of specimen increased with the increase of gas temperature or water vapor partial pressure. A corresponding decrease in the amount of Lu2Si2O7 phase was observed. Furthermore, by using the average weight loss rate for exposure times of ten hours, the influence of gas temperature and water vapor partial pressure on weight loss rate was examined, and the amount of recession under gas turbine conditions was calculated.


2009 ◽  
Vol 79-82 ◽  
pp. 775-778 ◽  
Author(s):  
Hong Li Liu ◽  
Chun Ying Tian

The self-healing ceramic coating against oxidation for carbon/carbon composite was fabricated via preceramic polymer pyrolysis process using polysilazane as preceramic and MoSi2, B4C powders as fillers. By means of SEM and XRD, the phase compose and microstructure of coating were characterized, and preliminarily study on its anti-oxidation ability and thermal shock resistance were conducted. The results showed that, the coating is composed of the resisting oxidation layer and the sealing layer. The thickness of the coating is about 50μm, and the coating is uniform and densified. Good contact at the interfaces is visible on the SEM photograph. At 1300°C temperature, the thermal shock resistance test was conducted 50 times, the weight loss rate was 2.12%. In range of 1200°C~1500°C, the anti oxidation ability of the coating is good.


2014 ◽  
Vol 584-586 ◽  
pp. 2121-2124
Author(s):  
Yan Shi ◽  
Hua Quan Yang ◽  
Xiang Li ◽  
Jia Zheng Li

Aging mechanism of dam concrete under the action of freeze-thaw damage was analyzed by testing macro and micro performance. The results show that compressive, splitting tensile and flexural strengths reached 58.4%, 61.3% and 57.8% of the initial values after 150 cycles. Strength is the most sensitive indicator of freeze-thaw damage, followed by weight loss rate, relative dynamic elastic modulus and ultrasonic velocity. After freeze-thaw damage, concrete structure becomes loose, porous amount gradually increased and pore size especially over 25nm expanded. Microcracks not only exist in the hydration products, but also destroy the bubbles structure in air entrained concrete, which is the main cause of freeze-thaw damage.


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